Mozilla Firefox before 3.5.12 and 3.6.x before 3.6.9, Thunderbird before 3.0.7 and 3.1.x before 3.1.3, and SeaMonkey before 2.0.7 do not properly restrict use of the type attribute of an OBJECT element to set a document's charset, which allows remote attackers to bypass cross-site scripting (XSS) protection mechanisms via UTF-7 encoding.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11735
https://bugzilla.mozilla.org/show_bug.cgi?id=579744
http://www.vupen.com/english/advisories/2011/0061
http://www.vupen.com/english/advisories/2010/2323
http://www.securityfocus.com/bid/43101
http://www.mozilla.org/security/announce/2010/mfsa2010-61.html
http://www.mandriva.com/security/advisories?name=MDVSA-2010:173
http://www.debian.org/security/2010/dsa-2106
http://support.avaya.com/css/P8/documents/100112690
http://support.avaya.com/css/P8/documents/100110210
http://secunia.com/advisories/42867
http://lists.opensuse.org/opensuse-security-announce/2010-10/msg00002.html
http://lists.fedoraproject.org/pipermail/package-announce/2010-September/047282.html
http://blogs.sun.com/security/entry/multiple_vulnerabilities_in_mozilla_firefox